We present a spectroscopic atlas of active galactic nuclei covering the region around the λλ8498, 8542, 8662 calcium triplet (CaT). The sample comprises 78 objects, divided into 43 Seyfert 2s, 26 Seyfert 1s, three starburst and six normal galaxies. The spectra pertain to the inner ~ 300 pc in radius, and thus sample the central kinematics and stellar populations of active galaxies. The data are used to measure stellar velocity dispersions (σ ) with both cross-correlation and direct fitting methods. These measurements are found to be in good agreement with each other and with those in previous studies for objects in common. The CaT equivalent width is also measured.We find average values and sample dispersions of WCaT of 4.6 ± 2.0, 7.0 ± 1.0 and 7.7 ± 1.0 Å for Seyfert 1s, Seyfert 2s and normal galaxies, respectively.We further present an atlas of [S III]λ9069 emission-line profiles for a subset of 40 galaxies. These data are analysed in a companion paper which addresses the connection between stellar and narrow-line region kinematics, the behaviour of the CaT equivalent width as a function of σ , activity type and stellar population properties.